01 - Preheat oven to 350°F.
02 - In a food processor, combine flour, powdered sugar, and salt. Add cubed butter and pulse until the mixture resembles coarse crumbs.
03 - Add egg yolk and 2 tablespoons cold water. Pulse until the dough just begins to come together, adding additional water as needed.
04 - Turn dough onto a lightly floured surface. Shape into a disk, wrap in plastic, and chill for 30 minutes.
05 - Roll out dough to 1/8-inch thickness. Fit into a 9-inch tart pan, trim any overhang, prick the base with a fork, and freeze for 10 minutes.
06 - Line the crust with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes, remove weights, then continue baking 8 to 10 minutes until golden. Cool slightly.
07 - Lower the oven temperature to 300°F.
08 - In a mixing bowl, whisk heavy cream, granulated sugar, eggs, egg yolks, lemon zest, lemon juice, and salt until smooth.
09 - Pour the lemon mixture into the baked crust. Bake for 20 to 25 minutes, until edges are set and the center is just slightly jiggly.
10 - Cool tart completely on a wire rack, then refrigerate at least 1 hour before serving.
11 - Dust with powdered sugar and add berries or candied lemon slices as desired.